Unless you are making regular contact with a shore party and you come up "overdue" or MIA, no one and no thing is going to trigger a search for you. (Ignoring EPIRBs which still have to be triggered by someone to make contact with a shore party.)

Bottom line, have a float plan.

"We should be back around...Call this number and declare us overdue on..." and hand someone a pre-filled SAR form. The USCG form used to be quite a few pages long, asking for details like yacht make, number of sails, color of hull and deck, all sorts of things your friends are not likely to have at the tip of their tongue, that can help get a SAR effort launched ASAP.